Giant swiftlet explained

The giant swiftlet (Hydrochous gigas), also known as the waterfall swift, is a species of bird in the swift family, Apodidae. It is the only member of the monotypic genus Hydrochous. It is found in Malaysia, Sumatra and Java, where its natural habitats are subtropical or tropical moist montane forests and rivers. It is threatened by habitat loss.

The giant swiftlet has the largest average wingspan of all the swiftlets, at 150 millimeters.^[1] It is a fairly large swift that can grow to 16 cm in length. The female weighs 35 to 39 grams, and the male around 37 grams.^[2] Unlike other swiftlets, it builds its nest on a flat horizontal surface instead of molding it against a vertical surface with saliva.^[3]

It is not totally nocturnal but able to orientate visually in dim light.^[4]

Notes and References

1. Web site: The giant swiftlet, Collocalia gigas, Hartert and Butler. Somadikarta. Soekarja. October 1968. 9 June 2017.
2. Web site: Waterfall Swift (Hydrochous gigas). www.hbw.com. en. 2017-06-09.
3. Lee. Patricia L.M.. Clayton. Dale H.. Griffiths. Richard. Page. Roderic D.M.. 1996-07-09. Does behavior reflect phylogeny in swiftlets (Aves: Apodidae)? A test using cytochrome b mitochondrial DNA sequences. Proceedings of the National Academy of Sciences of the United States of America. en. 93. 14. 7091–7096. 10.1073/pnas.93.14.7091. 8692950. 38941. 0027-8424. free. 1996PNAS...93.7091L .
4. Medway. Lord. Wells. D. R.. 1969-10-01. Dark Orientation by the Giant Swiftlet Collocalia Gigas. Ibis. en. 111. 4. 609–611. 10.1111/j.1474-919X.1969.tb02570.x. 1474-919X.